/*
 *  Copyright (C) 2006 Apple Computer, Inc.
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Library General Public
 *  License as published by the Free Software Foundation; either
 *  version 2 of the License, or (at your option) any later version.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Library General Public License for more details.
 *
 *  You should have received a copy of the GNU Library General Public License
 *  along with this library; see the file COPYING.LIB.  If not, write to
 *  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 *  Boston, MA 02110-1301, USA.
 *
 */

#ifndef WTF_OwnPtr_h
#define WTF_OwnPtr_h

#include <algorithm>
#include <wtf/Assertions.h>
#include <wtf/Noncopyable.h>

namespace WTF
{

template <typename T> class OwnPtr : Noncopyable
{
public:
    explicit OwnPtr(T *ptr = nullptr) : m_ptr(ptr) { }
    ~OwnPtr()
    {
        safeDelete();
    }

    T *get() const
    {
        return m_ptr;
    }
    T *release()
    {
        T *ptr = m_ptr;
        m_ptr = nullptr;
        return ptr;
    }

    void set(T *ptr)
    {
        ASSERT(m_ptr != ptr);
        safeDelete();
        m_ptr = ptr;
    }
    void clear()
    {
        safeDelete();
        m_ptr = nullptr;
    }

    T &operator*() const
    {
        ASSERT(m_ptr);
        return *m_ptr;
    }
    T *operator->() const
    {
        ASSERT(m_ptr);
        return m_ptr;
    }

    bool operator!() const
    {
        return !m_ptr;
    }

    // This conversion operator allows implicit conversion to bool but not to other integer types.
    typedef T *(OwnPtr::*UnspecifiedBoolType)() const;
    operator UnspecifiedBoolType() const
    {
        return m_ptr ? &OwnPtr::get : nullptr;
    }

    void swap(OwnPtr &o)
    {
        std::swap(m_ptr, o.m_ptr);
    }

private:
    void safeDelete()
    {
        typedef char known[sizeof(T) ? 1 : -1];
        if (sizeof(known)) {
            delete m_ptr;
        }
    }

    T *m_ptr;
};

template <typename T> inline void swap(OwnPtr<T> &a, OwnPtr<T> &b)
{
    a.swap(b);
}

} // namespace WTF

using WTF::OwnPtr;

#endif // WTF_OwnPtr_h
